diff --git a/packages/core/src/edge/common.ts b/packages/core/src/edge/common.ts
index 22c2cfb..87623b6 100644
--- a/packages/core/src/edge/common.ts
+++ b/packages/core/src/edge/common.ts
@@ -5,7 +5,7 @@ export type GenericRawProjection<T> = ObjectOrValue<
   Ref | string | boolean | 0 | 1 | T
 >;
 export type GenericProjection<T> = {
-  [name: string]: Ref | string | false | T;
+  [name: string]: Ref | false | T;
 };
 
 export function capitalize(s: string) {
diff --git a/packages/core/src/edge/edge-builder.ts b/packages/core/src/edge/edge-builder.ts
index 1fc2d52..8c69023 100644
--- a/packages/core/src/edge/edge-builder.ts
+++ b/packages/core/src/edge/edge-builder.ts
@@ -16,7 +16,11 @@ import {
 import { DirectiveBuilder } from '../directive';
 import { Ref } from '../ref';
 import { Runnable } from '../types';
-import { FieldBuilder, BuildFieldArgs } from '../field';
+import {
+  FieldBuilder,
+  CustomFieldBuilder,
+  BuildFieldArgs,
+} from '../field';
 import { AggregationBuilder } from '../aggregation';
 
 type OpBuilders = OperatorBuilder | LogicalOperatorBuilder;
@@ -24,7 +28,7 @@ export type RawProjection = GenericRawProjection<
   EdgeBuilder | FieldBuilder | AggregationBuilder
 >;
 export type Projection = GenericProjection<
-  EdgeBuilder | FieldBuilder | AggregationBuilder
+  EdgeBuilder | FieldBuilder | CustomFieldBuilder | AggregationBuilder
 >;
 
 export interface NameGenerators {
@@ -83,6 +87,9 @@ export class EdgeBuilder extends FieldBuilder {
           if (existing) return r;
           v = new FieldBuilder(undefined);
         }
+        if (typeof v === 'string')
+          v = new CustomFieldBuilder(v);
+
         if (
           typeof v !== 'object'
           || v instanceof Ref
@@ -100,7 +107,6 @@ export class EdgeBuilder extends FieldBuilder {
 
         if (
           !existing
-          || typeof existing === 'string'
           || existing instanceof Ref
           || existing instanceof AggregationBuilder
         ) {
diff --git a/packages/core/src/field/custom-field-builder.ts b/packages/core/src/field/custom-field-builder.ts
new file mode 100644
index 0000000..ee62c7c
--- /dev/null
+++ b/packages/core/src/field/custom-field-builder.ts
@@ -0,0 +1,4 @@
+import { FieldBuilder } from './field-builder';
+
+export class CustomFieldBuilder extends FieldBuilder {
+}
diff --git a/packages/core/src/field/index.ts b/packages/core/src/field/index.ts
index 7b8c6d7..1680382 100644
--- a/packages/core/src/field/index.ts
+++ b/packages/core/src/field/index.ts
@@ -1,2 +1,3 @@
 export * from './field-builder';
 export * from './field';
+export * from './custom-field-builder';